metrics/base: log whether drives have seek penalties.

components/metrics/proto/system_profile.proto

Index: components/metrics/proto/system_profile.proto
diff --git a/components/metrics/proto/system_profile.proto b/components/metrics/proto/system_profile.proto
index c73d8a95e8086a6bf9935297078e354ed3a48dd0..b9acc029385587ce654b73a1fd80957f73dc0a39 100644
--- a/components/metrics/proto/system_profile.proto
+++ b/components/metrics/proto/system_profile.proto
@@ -92,7 +92,7 @@ message SystemProfileProto {
   }
   optional OS os = 5;
 
-  // Next tag for Hardware: 16
+  // Next tag for Hardware: 18
   // Information on the user's hardware.
   message Hardware {
     // The CPU architecture (x86, PowerPC, x86_64, ...)
@@ -261,6 +261,15 @@ message SystemProfileProto {
     // Lists vendor and product ids of external touchscreens.
     // Logged on ChromeOS only.
     repeated TouchScreen external_touchscreen = 15;
+
+    message Drive {
+      // Whether this drive incurs a time penalty when randomly accessed.
+      optional bool has_seek_penalty = 1;
+    }
+    // The drive that the application executable was loaded from.
+    optional Drive app_drive = 16;
+    // The drive that the current user data directory was loaded from.
+    optional Drive user_data_drive = 17;
   }
   optional Hardware hardware = 6;